The pistol-ready HOLOSUN HE509T X2 Enclosed Pistol Reflex Sight houses next-level performance inside ultra-rugged Grade-5 titanium, boasting double the tensile strength and up to 5x the fatigue strength of 7075 aluminum. The HE509T X2 offers up to 50,000 hours of battery life with the added peace of mind of Solar Failsafe Technology to keep the sight powered when the battery eventually fails. Automatic brightness adjustment brightens in sunlight and dims down to match ambient lighting conditions when indoors. Super LEDs with 12 selectable brightness settings deliver a wide range of intensities to best match lighting conditions. Shake Awake Technology shuts the LED off to conserve power when not in use and offers hands-free activation with just a shake. Multilayer coatings reduce glare, while facilitating maximum light transmission and resistance to wear. You'll enjoy crystal-clear sight acquisition with a parallax-free field of view and unlimited eye relief. HOLOSUN HE509T X2 Enclosed Pistol Reflex Sight is powered by included CR1632 battery. Included 509T RMR adapter plate not compatible with ZEV or Shadow Systems-style RMR interfaces. Ultra-rugged Grade-5 Titanium housing 50,000 hours of battery life Solar Failsafe Technology backs up battery Automatic brightness adjustment 12 selectable brightness settings Shake Awake hands-free activation